The anthocyanidins of formula I are known per se and have been obtained by extraction and purification from flowers (for instance from winter aster, violet, petunia, pansy, euphorbia) and from fruit or the skin thereof (for instance from sweet and sour cherries, strawberries, cranberries, whortleberries, blackcurrants). They have also been proposed for use in the therapeutical field as agents (i) having a vitamin-like action (see U.S. Pat. No. 2,744,893) or prolonging the retention of vitamin C (see U.S. Pat. No. 2,647,058) and (ii) improving the resistance and the permeability of capillaries (see French BSM No. 6760M) and therefore being useful for improving visual acuity by night (see British Pat. No. 1,007,751).
It has now been found that anthocyanidin compounds of formula I (i) reduce the retention of cholesterol in arteries, (ii) improve the collagen synthesis which is disturbed by hypertension and diabetes, and (iii) normalize the flexibility and deformability of red blood cells in patients suffering from artery disorders, and that said anthocyanidin compounds are surprisingly useful and efficient in the treatment of heart and artery disorders such as atheroma and, in a general manner, angiopathies (i.e. impairment of the vasculary wall especially in connection with hypertension diabetes, and other metabolic diseases and/or ischaemiae resulting therefrom).